Halopyridyl thioalkylthio cyanates

ABSTRACT

Compounds corresponding to the formula   WHEREIN X represents chloro or bromo and n represents an integer of 2 to 4, are prepared. These compounds have been found to be useful as bactericides and fungicides.

United States Patent [191 Domenico June 17, 1975 HALOPYRIDYL THIOALKYLTHIO CYANATES [75] Inventor:

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

[22] Filed: Apr. 15, 1974 [21] Appl. No.: 460,831

Penelope B. Domenico, Fairfax, Va.

[52] US. Cl 260/294.8 G; 424/263 [51] Int. Cl C07d 31/50 [58] Field of Search 260/294.8 G, 294.8 F

[56] References Cited UNITED STATES PATENTS 3,758,482 9/1973 Domenico 260/294.8 G

3,787,422 l/l974 Domenico 260/2948 F 3,787,425 l/l974 Domenico 260/294.8 G

OTHER PUBLICATIONS Friedrich et al., Chem. Abstracts, Vol. 63, (6), 6971F to 6972-F (Sept. 1965).

Primary Examiner--Alan L. Rotman Attorney, Agent, or Firm-S. Preston Jones; William M. Yates [57] ABSTRACT Compounds corresponding to the formula sczi scw 6 Claims, No Drawings HALOPYRIDYL THIOALKYLTHEO CYANATES An alternative procedure for the preparation of the above halopyridyl thioalkyithioc 'anates involves the PRIOR ART reaction of an appropriate halo siibstituted alkai metal thiopyridine with chloromethylthiocyanate in the pres- Various pyridyl thioalkylthiocyanates are known and ence of a reaction medium or solvent. This reaction can are taught in Belgian Pat. No. 722,018. Other related be represented as follows:

SI-4e SCHZSCN .fialze ua i X clcn so. A a a x nacl n i1 compounds are taught in Chemical Abstracts, Vol. 63, wherein X, n, and Me are as hereinbefore defined. (1965) 6971f through 6972f, especially 6972b; and In carrying out this reaction, the alkali metal thi- U.S. Pat. No. 3,758,482. opyridine can be prepared in situ by the reaction of a l5 halornercaptopyridine with an alkali metal in a solvent. SUMMARY OF THE INVENTION This in situ preparation is usually carried out by first The present invention is directed to halopyridyl dissolving the alkali metal in an alkanol and admixing hi lky y n rr p n ing o e or this, at room temperature, with a solution of the halomercaptopyridine in an alkanol. The chloromethylthi- SCH SCN ocyanate can thereafter be added directly to the alcoholic solution of the halo alkali metal thiopyridine and I this mixture refluxed until the completion of the reac- N tion, usually from about 30 minutes to about 2 hours.

After the completion of the reaction, the reaction mixture is filtered to remove the alkali metal chloride salt In this and succeeding formulae X represents ChlOX'O by-p; 0duct The 31 01-101 is {hereafter removed by gvapor bromo and represents an integer of from 2 t0 oration under reduced pressure. The purified product For convenience, the COmPOLm embraced y the can be recovered from the residue by crystallization generic formula will be hsfeiflaftfir identified as from a solvent such as benzene, hexane or mixtures halopyridyl thioalkylthiocyanates. th r f,

The halopyridyl thioalkyithiocyanates of the present invention are crystalline solids or oils which are of low DESCRIPTIQN OF SOME PREFERRED solubility in water and of moderate solubility in com- EMBODIMENTS mon organic Solvents- Thes mp n have low p y- The following examples illustrate the present inventotoxicity and are suitable for use as bactericides and i n and the manner by which it can be practiced, but, fungicides. as such, should not be construed as limitations upon the v The compounds of the present invention can be prell scope f th sam pared by the reaction of an appropriate halo substi EXAMPLE} tuted 4-[(chloromethyl)thiolpyridine with an alkali metal thiocyanate in the presence of a solvent. This re- 40 2,6-Dichloro-4-[( thiomethyl)thiocyanato1pyridine action can be represented as follows:

cu cl cu scu Reaction X MeSCN Medium I X MeCl wherein X and n are as hereinbefore defined and Me SCU SCN represents sodium, lithium, potassium, cesium or rubidium. I

In carrying out this reaction, the reactants are con- (1 W Cl tacted together in the presence of an inert reaction the: dium or solvent such as, for example, dimethylformamide, hexamethylphosphoramicle, or 4-formylmor- To a solution of 5.0 7 grams (0.219 mole) 2,6- pholine. The reaction is preferably carried out at room dichloro-4-chloromethylthio pyridine ill 15 milliliters temperature, although temperatures in the range of of dimethylformarnide was added, at room temperature about 0 to about 100C can be employed. Thereaction with stirring, a solution of 3.19 grams (0.329 mole) of is usually carried out at atmospheric pressure. While potassium thiocyanate in 15 milliliters of dimethylthe reaction consumes the reactants in equimolar formamide. The mixture was stirred at room temperaamounts, it is preferred that about a 10 to about a 150 ture for about one hour and heated to 60-80C and percent excess of the alkali metal thiocyanate be emstirred at a temperature within this temperature range for about 1 hour. At the completion of this reaction,

ployed.

The reactants are maintained together, under agitathe reaction mixture was filtered to remove the potastion, until the reaction is complete. The required reacsium chloride by-product and the resultant mother iltion time is usually between about 30 minutes and 4 quor poured into ice water. The water was decanted off hours. Upon completion of the reaction, the reaction and fresh water added to sticky solid which remained.

mixture is diluted with cold water to precipitate out any Upon washing in the water, a waxy solid was obtained solid product. The solid product can be purified, if deand this solid was recovered by filtration. The SOlld was sired, by recrystallization from benzene, hexane, pentaken up in benzene and dried with sodium sulfate. The

tane or mixtures thereof. benzene was removed and the solid was recrystallized in hexane. The desired 2,6-dichloro-4-[(thiomethyl)- thiocyanato1pyridine product was recovered as a fluffy yellow-tan solid. The product was recovered in a yield of 3.0 grams (55 percent of theoretical) and melted at 55C. Upon analysis, the product was found to have chlorine and sulfur contents of 27.84 and 25.48 percent, respectively, as compared with the theoretical contents of 28.23 and 25.53 percent respectively, as calculated for the above named compound.

EXAMPLE II 2,3 ,5-Trichloro-4-[ (thiomethyl)thiocyanato]pyridine l S Cl 1 2 S CH A solution was prepared by dissolving 0.77 grams (0.023 mole) of sodium metal in 25 milliliters of 28 absolute ethanol. This soluton was slowly added to a solution of grams (0.023 mole) of 2,3,5-trichloro-4- mercaptopyridine in hot ethanol. This mixture was re-- fluxed for 45 minutes and 2.7 grams (0.025 mole) of chloromethylthiocyanate was added thereto. This mixture was refluxed for 1 hour. The sodium chloride which formed was removed by filtration, followed by the removal of the ethanol by evaporation under reduced pressure. The oil which remained as a residue was washed with a mixture of benzene and hexane. The solvent mixture was removed. The residue was allowed to stand and crystals started to form. Hexane was added and after crystal formation ceased the hexane removed. The residue was cooled and filtered to recover the desired 2,3,5-trichloro-4-[(thiomethyl)thiocyanato]pyridine product. The product melted at 96C and upon analysis was found to have carbon, hydrogen, chlorine, nitrogen and sulfur contents of 29.8, 1.3, 36.9, 9.4 and 22.2 percent respectively, as compared with the theoretical contents of 29.5, 1.1, 37.3, 9.8 and 22.5 percent respectively, as calculated for the above named structure.

EXAMPLE III 2,3,5 ,6-Tetrachloro-4-[(thiomethyl)thiocyanato]- pyridine scmscn C1 Cl To a stirring solution of 10.0 grams (0.34 mole) of 2,3,- 5,6-tetrachloro-4--chloromethylthiopyridine in 50 milliliters of dimethylformamide was added, at room temperature, 3.4 grams (0.035 mole) of potassium thiocyanate in 25 milliliters of dimethylformamide. The mixture was allowed to stir for 1 hours at room temperature. The temperature of the mixture was raised to 40C and then to 100C and the mixture stirred at this temperature for 1 hour. After completion of the reaction, the reaction mixture was poured into cold water. The yellow-tan solid which precipitated was recovered by filtration. The crude solid was taken up in benzene and dried with sodium sulfate. Aportion of the benzene was evaporated off and hexane was added. The mixture was cooled and the 2,3,5,6-tetrachloro-4- [(thiomethyl)thiocyanato]pyridine product was recovered by filtration and thereafter recrystallized from hexane. The product melted at 1 18- 1 20C and was re-.

covered in a yield of 4.8 grams (45 percent of theoretical). Upon analysis, the product was found to have carbon, hydrogen, chlorine, nitrogen and sulfur contents of 26.44, 0.73, 44.42, 8.77 and 19.86 percent, respectively, as compared with the theoretical contents of 26.23, 0.63, 44.25, 8.76 and 20,00 percent, respectively, as calculated for the above named compound.

The following compounds of the present invention are prepared in accordance with the methods hereinbefore set forth.

2,6-Dibromo-4-[ (thiomethyl )thiocyanato ]-pyridin'e having a molecular weight of340.05;

3 ,5 -Dichloro-4-[ thiomethyl )thio cyanato pyridine having a molecular weight of 251.15;

2 ,3 ,5-Tribromo-4-[ (thiomethyl) thiocyanato pyridine having a molecular weight of 418.97;

3 ,6-Dichloro-4-[ thiomethyl )thiocyanato pyridine having a molecular weight of 251.15; and

2,3,5,6-Tetrabromo-4-[(thiomethyl)thiocyanato]- I pyridine having a molecular weight of 497.89.

In accordance with the present invention, it has-been discovered that the halopyridylthioalk'yl thiocyanates can be employed for the control of may bacterial and fungal organisms. In still further operations, the corn such products by micro-organisms. Also, the com-' pounds can be distributed in textiles or cellulosic mate rials to preserve and protect such products from the attack of the organisms of rot, mold and decay. The exact concentration of the toxicant toflbe employed in the treating compositions is not critical and may vary considerablyprovidedthe required dosage of the effective agent is supplied in the ink, adhesive,

soap, cutting oil, polymeric materiaLpaint, textile, lpaper, or growth medium. The concentration of toxicant in liquid compositions generally is from about 0.0001 to 50 percent by weight. Concentrations up to per-' cent by weight are oftentimes conveniently (employed,

particularly in concentrate compositions. dusts the'.

concentrations of the toxicant can be fromabout 0.l to 95 percent by weight. In compositions to beemployed as concentrates, the toxicants can be present in a con-.

centration of from 5 to 98 percent by weight.,For use 7 as a spray, it is often convenient to preparethe .com-

pounds as wettable powders. t

In a representative operation,

of 10 parts by weight of the compoundper million Pa ts of agar was found to give 100 percent kill and control.-

of the organisms Staphylococcus aureus, Candida albicans, Mycobacterium phlei, Bacillus subtilis, Trich ophy ton mentagrophytes, Candida pelliculosa, P ul lularia. pullulans, Cephaloascus fragans, Ceratocystis ips,. Tri- 2,6-dichloro-4- [(thiomethyl )thiocyanato]pyridine ,when employed as. the sole toxicant in a nutrient agar at a concentration chloderma sp Madison P-42, Rhizopus nigricans and Aspergillus terreus.

In an additional operation, 2,3,5-trichloro-4- [(thiomethyl)thiocyanato1pyridine was found to give 100 percent kill and control of the organisms Staphylococcus aureus, Candida albicans, Trichophyton mentagrophytes, Bacillus subtilis, Aspergellus terreus, Cadida pelliculosa, Pullularia pullulans, Mycobacterium pheli, Ceratocystis ips, Cephaloacus fragans, Trichoderma sp. Madison P-42, and Rhizopus nigricans, when employed as the sole toxicant in a nutrient agar at a concentration of about parts by weight of the compound per million parts of agar.

In another operation, 2,3,5,6-tetrachloro-4- [(thiomethyl)thiocyanato]pyridine was found to give 100 percent kill and control of the organisms Mycobacterium phlei, Trichophyton mentagrophytes, Cephaloascusfragans, Aspergillus terreus, Ceratocystis ips and Trichoderma sp. Madison P-42, when employed as the sole toxicant in a nutrient agar at a concentration of about 10 parts by weight of the compound per million parts of agar.

What is claimed is:

1. A compound corresponding to the formula ISCHZSCN wherein X is chloro or bromo and n is an integer of from 2 to 4.

2. The compound of claim 1 corresponding to the formula lSCH SCN 3. The compound of claim 1 corresponding to the formula scH scN 

1. A COMPOUND CORRESPONDING TO THE FORMULA
 2. The compound of claim 1 corresponding to the formula
 3. The compound of claim 1 corresponding to the formula
 4. The compound of claim 3 which is 2,6-dichloro-4-((thiomethyl)thiocyanato)pyridine.
 5. The compound of claim 3 which is 2,3,5-trichloro-4-(thiomethyl)thiocyanato)pyridine.
 6. The compound of claim 3 which is 2,3,5,6-tetrachloro-4-((thiomethyl)thiocyanato)pyridine. 